The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1887-04-02
Correspondence Baltimore County Union.
SCIENTIFIC MISCELLANY.
FoRrsr-DnsrnorERs OF AUSTRALIA.

SCIENTIFIC MISCELLANY.
FoREsT-DESTRoYERS OF AUSTRALIA.
The crop destroying rabbit appears to be not
the only animal plague of Australia. The decay
of the forests is traced by Rev. P. Macpherson of
the Royal Society of New South Wales, to the
opossums. After much investigation, it was as
certained that single animal would devour about
200 leaves of the Eucalyptus, or blue gum tree, in
night; proving that the $4,000 opossums killed
annually in one county of Victoria were sufficient
to destroy upwards of Il, 900 trees and lay bare
space Of 700 acres, or more than a square mile.
THE sALT-RooK OF LOUISIANA.
The salt deposit of Petit Anse, in southwestern
Louisiana is one of the most remarkable known.
1t is of pure crystal salt, covering $50 to
unknown depth, having been penetrated 14O feet.
1t is from one to six feet below sea-leve and the
earth over it is from ten to 1873 feet thick. On
the salt, beneath the earth, have been found re-
mains of prehistoric animals, and Indian relics.
Above the salt and the animal remains, and of
more recent deposition, are strata of coal and
sandstone.
THE GREEN-EYED.
Mons Topinard has called attention to the extreme
rarity of greenisb eyes in Europe, only six cases
having been observed by Prof. Virchow in 6,O00,-
600 Germans. With us green-eyed person must
be fully as uncommon sight. Yet Chinese an
nails record that green eyes abound in parts of
Asia, and Pallas notes that they are met with in
Siberia.
Most of the ordinary domestic filters-and es-
pecially those of spongy iron, carbon, stones,
gravel and cellulose-are pronounced by Ger
man physician, DR.. Plagge, to be of little or no
value for purifying water, as they do not remove
the living organisms, or bacteria, and allow such
germs as those of typhus and cholera to pass with
out hindrance. Clay and asbestos filters were
found to have some effect in stopping infectious
matters, but were not long reliable. Hesse has
recommended strongly compressed asbestos and
especially dense cells of clay as yielding water
permanently germ free, but of these fltering
terials DR.. Pagge is unable to speak from his own
observation of experiment.
A wooDEN-LEGGED ROMAN.
Having fresh in mind the discovery that artif-
cial teeth were used by the ancient Greeks and
Romans, one can hardly feel surprised at finding
that artificial limbs no modern innovation
Historians have vaguely alluded to substitutes for
arms and legs in ante Christian days, but speci-
men of such work is actually in existence, and
forms unique relic in the Museum of the Royal
College of Surgeons, London. 1t is an artificial
leg dating from about 800 B. c., and was unearth-
ed with the cripple's skeleton at Capua in 1885,
1t is made of pieces of thin BRONZE the lower two
thirds having been nailed to a wooden core-now
decayed-and the upper third being hollow.
LABORATORY GEMS.
Real diamonds have been produced artifcally
in Scotland, but were too small and expensive to
be commercial success Paste limitations have
been so perfected by French chemists that they |
serve the decorative purpose of the genuine stones
and can only be detected by the test of hardness
Artificial rubies and sapphires have the same COM
position as the natural minerals, and nearly equal
hardness.
VACCINATION.
incubation with small pox as preventive |
measure was known to the Arabs and Chinese as |
early as the tenth century, but it was decried by |
physicians and only practised by women. In |
India it was common among the Brahmins, and |
public crier proclaimed that he had smallpox
virus to sell. In IVY the operation came under
the notice of the wife of the English Ambassador
in Constantinople, and she caused it to be tried
in England, where several hundred persons were
inoculated before the practice discredited and
condemned. In 1928 it was introduced into
France, and, though condemned by official DEGREES
in 1853 and 1853, it continued to be practised
there until the use of vaccine was substituted for
it. Vaccination appears to have been earlier
known in Asia, but, however this may be, farm
servants in the south of France were aware that
those who had been affected by cow-pox escaped
smallpox. This fact came to Jenner's knowledge,
and led to experiments which resulted in 1898 in
the announcement of one of the greatest discover
les of modern medicine, which, though strongly
opposed at first, has since effected practical
Inhalation of a terrible scourge. The principle of
preventive incubation thus applied to small pox
seems likely to prove effective in all other germ
diseases. Since 1881 Pasteur's vaccinations for
the anthrax of sheep and cattle and the cholera Of
fowls have saved French farmers enormous sums,
and in hs Later Nth
vaccination may be effective even after the disease
germs have been implanted in the system. The
theory of vaccinations is best expounded by Tyndal,
who supposes that the wild form of disease with
which the body is inoculated consumes the sub
stances of the blood which might otherwise 60 to
feed the more virulent germs.
MISCELLANEOUS. ..s
The simple process of slipping tube into the
larynx through the mouth is being substituted
for the formidable surgical operation OF tracheoto-
my in Group and diphtheria, with good results.
A Glasgow yacht, destined for pearl-fshing IN
South Australian waters, has been fitted with
electrical apparatus expected to light up the
water to the great depth of seventeen fathoms..
An Austrian investigator has hit upon an in
genious process for siIvering iron. The surface
first covered with mersury, the silver is deposited
extraordinarily as the electroplating of copper,
and the mercury is then evaporated by heat OF
about 600 degrees.
Among the remarkable woods of South Africa
is sneezewood (Pterorylon utite1, which IN dura'
bility is said to surpass even Lignum- pro-
ducing machine bearings which have been known
to outlast those of both brass and iron.